碱性铜粗抛液中氧化剂对化学机械平坦化的影响

Effect of the Oxidant in Alkaline Copper Fast Polishing Slurry on the Chemical Mechanical Planarization

针对不含腐蚀抑制剂苯并三氮唑(BTA)的碱性铜粗抛液,通过对3英寸(1英寸=2.54 cm)铜片上的动态抛光速率和静态腐蚀速率的研究来模拟评估氧化剂对晶圆表面平坦化的影响。在12英寸铜镀膜片和TM1图形片上分别研究氧化剂体积分数对表面平坦化的影响。实验结果表明:动态抛光速率和静态腐蚀速率均随着氧化剂体积分数的增加先逐渐增大,达到最大值,然后下降,趋于平缓。片内非均匀性和剩余高低差均随H2O2体积分数的增加,先呈下降趋势,后缓慢上升。当氧化剂体积分数为3%时,动态去除速率(vRR)为398.988 nm/min,静态腐蚀速率vER为6.834 nm/min,vRR/vER比值最大,片内非均匀性最小为3.82%,台阶高低差最小为104.6 nm/min,此时晶圆片有较好的平坦化效果。

The effect of the oxidant on the wafer surface planarization was evaluated for alkaline copper fast poli-shing slurry without the corrosion inhibitor BTA by studying on the dynamic removal rate and the static etch rate in 3 inch（ 1 inch = 2. 54 cm） copper sheet. The effects of oxidant volume traction on planarization were studied in 12 inch copper sheet and 12 inch TM1 wafer respectively. The experimental results show that both the dynamic removal rate and the static etch rate increase with the increment in oxidant volume fraction initially until gradually reach the maximum,then decrease and become flat. The within-wafer-nonuniformity（ WIWNU） and the step height have a downward trend first,and then slowly increase with the increase in H2O2 volume fraction. It is the best effect on the wafer planarization when the volume fraction of the oxidant is 3%,with 398. 988 nm / min dynamic removal rate,6. 834 nm / min static etch rate,a maximum vRR/ vERratio,and minimum of WIWNU and step height are3. 82% and 104. 6 nm / min respectively.